Method of flaring tubing



Dec. 26, 1950 .1. R. wELsHMAN METHOD 0F' FLARING TUBING Original FiledNov. 1l, 1943 I N V EN TOR.

Jam es E. Wels/nan JOC- Patented Dec. 26, 1950 METHOD F FLARING TUBINGJames R. Welshman, Cranston, R. I., assigner to Grinnell Corporation,Providence, R. I., a corporation of Delaware Original applicationNovember 11, 1943, Serial No. 509,931, now Patent No. 2,437,285, datedMarch `9, 1948. Divided and this application February v26, 1948, SerialNo. 11,120

This invention relates to improvements in a method of flaring tubing.More especially it has to do with the formation of a tapering flaredportion at the end of tubing so that the tubing may be engaged by aflared tting.

My improved method is particularly adapted for flaring tubing which hasAa weak longitudinal seam, or similar longitudinal weakness, likely toproduce a split in the tube wall when an attempt is made to flare thetubing in the usual manner with the means customarily employed.

It is an object of my invention to provide a method of aring such tubingwithout rupture of the tube Wall and to provide simple but highlyeffective apparatus for practicing the improved method.

The best mode in which I have contemplated applying the principles of myinvention is described in the following text and shown in theaccompanying drawings but the latter are to be deemed merelyillustrative for it is intended that the patent seall cover by suitableexpression 'in the claim whatever Vfeatures o1 patentable novelty existin the invention disclosed.

In the accompanying drawings,

Figure l is anexploded view of the several Vparts of a preferred form ofapparatus for flaring tubing in accordance with my improved method;

Figure 2 is a medial section showing the parts of ney improved apparatusand a piece of tubing in the relative positions they Yoccupy when theflaring operation is about to be performed;

Figure 3 is a section on line 3-3 of Figure 2;

Figures 4, '5 and 6 show the tubing and immediately adjacent parts ofthe apparatus in their relative positions at different stages of theflaring operation;

Figure 7 shows the end of the tubing as it generally appears whenremoved from the apparatus; and

Figure 8 shows the finished ared end.

The essence of my improved method resides in holding the externalsurface of a portion adjacent the end of the tubing to a diameter lessthan the greatest diameter of the external surface of the flared portionof the tubing. The thickness of the wall close bv the end is reduced.however, and part of the wall material is swaged downward slightly intothat portion of the tubing which is flared. By thus holding the edge ofthe tube from any substantial expansion, coupled with the slightupsetting or swaging of the material toward Where the greatest stretchof the tubing will normally occur. it is possible to flare the presentavailable tubing without rupture or weakening of the tube wall.

1 Claim. (Cl. 153--79) Referring now to Figure l, there is shown inseparated relation the various parts of a preferred form of flaringmeans for practicing my invention` These comprise a block or clampingring I0, a pair of jaw holders I2, I4, a pair of flaring jaws I6, I3,and a flaring plunger 2B.

The block I0 may be secured in a vise but its outer surface is lrnurledso that it can be held in ones hand. It has a tapered axial hole Iaextending through it.

The jaw holders i2, I4 have exterior curved surfaces I2a, Ma tap-ered tot the wall of the hole Illa in the clamping ring lil, and also haveopposed flat surfaces IZb and Illb. Each holder has a semi-cyclindricalrecess I2C, Mc which terminates in an enlargement i201, Md at the uplerend to provide a shoulder I2e, Me. When the holders are together theyprovide a cylindrical hole between them for the reception of the Haringjaws I-6 and I8.

These jaws have external cylindrical surfaces I 6a, 18a and externalshoulders I 5b, Ib to t the hole formed by the holders I2, ifi. Aclamping jaw may be held to a holcer by a screw 22, whose threadedportion passes through a shouldered hole in the holder and screws into atapped hole in the jaw. Each jaw has for most of its length asemi-cylindrical recess |50, Ic. butat its upper end is particularlyformed with tapered surfaces ISd, lad which diverge outward et an anglefrom the axis equal to one-half the degree of flare to be imposed on thetubing- 24. Each outwardly tapered surface ltd Id extends al^ng the axisas far as desired to make the lens-5th of the flare wanted. From thering of greatest diameter of the outwardly flared surface, the wall istapered inward sharply, as at ite and le, to terminate in a shortcylindrical portion ttf, Isf, a little larger than the outside dimensionof the unilared tube.

The aring plunger 28 has a cylindrical portion 29a substantiallv thesame size as the hole in the tubing to be flared. From this portion, toanother cylindrical portion 2F5b, is a tapered or flaring surface 20cmaking an angle with the axis of the plunger equal to the degree offlare to be imposed on the tubing, The diameter of the largercylindrical portion 2th of the plunger is slightly less than that of theshort cylindrical hcle formed by the portions if and I'Sf of the flaringjaws.

In the practice of my improved method the tubing 24 to be flared isplaced between the jaws I6 and I8 with its end 24a extending slightlybeyond the ends of the jaws as shown in Figure ,2. The jaws are set inthe holders I2 and I4 and the latter in the ring I0. The larger ends ofthe holders are preferably tapped lightly with a hammer to tighten thejaws against the tubing. The plunger 20 is inserted in the tubing withits ared portion 26e resting on the edge 24a of the tube. The latteredge, by the way, need not be cut or finished with any special care butmay be the edge left when tubing is cut with a hack saw or pipe cutter.

The plunger is now subjected to hammer blows until the flaring iscompleted. In Figures 4, 5 and 6 I have attempted to illustrate what Ibelieve occurs as the aring takes place. As the plunger is driven intothe tubing the holders I2 and I4 settle very firmly into the ring I0,causing the jaws I6 and I8 to grip more tightly the tubing 24 betweenthem. As the flared surface 20c of the plunger moves downward it appliesan increasing fricfional force solely to the inner surface of the tubingbetween the edge 24a and the uniared surface of the tubing. The axialcomponents of this force act with swaging effect on the tube Wall,gradually thinning it opposite the portions I Bf and l8f of the jaws.Part of the metal displaced by the swaging action may move upward toswell very slightly the edge 24a of the tubing, but for the most part itmoves downward and apparently slightly thickens the tubing just belowthe said portions IBf and If of the jaws.

As the progress of the plunger continues the radial components of theabove mentioned frictional force act to displace the wall of the tubingoutward into the space around it, formed by the tapered surfaces Id,I8d, I6e and I8e, until when the plunger bottoms (that is, when thelower end of its flared portion is opposite the lower ends of the flaredportions of the aring jaws) the wall of the tube is dared outward asdesired and as shown and thus produce the finished ilared end 24e fshown in Figure 8f Examination of the 11a-red end discloses no rupture,tear or crack in the tubing. The entire flared portion is intact. Ifanything, it may be slightly stronger than would be the case if flaredin the usual way, because despite the increased circumferential size,the wall thickness of the flared portion is not appreciably thinned butusually measures as thick as the original thickness of the tube wall.

This application is a division of original application Serial No.509,931, filed November 11, 1943, issued March 9, 1948, as LettersPatent No, 2,437,285, in which in response to a requirement for divisionthe method claims were cancelled, applicant then reserving the right tolile a divisional case pertaining to the method disclosed in theoriginal application.

I claim:

The method of forming a tapering flared portion on tubing whichcomprises holding an unilared portion of the tubing on one side of theportion to be flared against displacement in the direction of the axisof the tubing and holding the external surface of the tubing on theother side of said portion to be ared against displacement in directionradial to said axis, applying an increasing frictional force solely tothe inner surface of the tubing between its end and the unflaredsurface, the axial components of said force simultaneously displacing indirection along the axis a portion of the wall of the tubing whoseexternal surface is being held against radial displacement, and theradial components of said force displacing the Wall of said tubing atsaid portion to be flared outward progressingly from the said unfiaredportion to form the desired tapering ared portion.

I JAN/IES R. WELSHMAN.

REFERENCES CITED The following references are of record in the le ofthis patent:

` UNITED STATES PATENTS Number Name Date 410,000 Matheson Aug. 27, 1889412,389 Isherwood Oct. 8, 1889 606,046 Chillingworth June 21, 18981,724,920 Fischer Aug. 20, 1929 1,791,887 Davies Feb. 10, 1931 1,804,815Schultis May 12, 1931 1,817,854 Sorensen Aug. 4, 1931 1,851,276 GordonMar. 29, 1932 1,911,186 Gordon May 30, 1933 2,024,803 Nelson Dec. 17,1935 2,124,743 McMahon July 26, 1938 2,211,242 McIntosh Aug. 13, 19402,437,285 Welshxnan Mar. 9, 1948

